Locating C source code


 
Thread Tools Search this Thread
Top Forums UNIX for Dummies Questions & Answers Locating C source code
# 1  
Old 04-11-2006
Locating C source code

Hi,

I'm trying to locate where on the filesystem I can find the source code for C standard libraries. The reason why is I'd like to look at the implementation of "'atoi"'. I've tried a brutal search of "grep -r "atoi" *" from root as root but the search took too long.

I'm running redhat 7.3 if that helps.

Kind regards,

Chadwick.
# 2  
Old 04-11-2006
Just because you have Linux does not mean the source is still necessarily on your system. I'm assuming you're on Linux.

Plus, a lot of Linux source is machine-specific assembler, with a "generic" C version.
The file would be called atoi.s and it is probably inside a tarball with "glibc" somewhere in the middle of the tarball's filname. Your system probably uses the asm version.

The tarball for 3.4 glibc is named glibc.<version>.tar.gz - glibc.2.3.3.tar.gz
Here is the "C" version of atoi - which is likely NOT what you are using:
Code:
/* Copyright (C) 1991, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <stdlib.h>

#undef	atoi


/* Convert a string to an int.  */
int
atoi (const char *nptr)
{
  return (int) strtol (nptr, (char **) NULL, 10);
}

strtoul.c: is in the next post
# 3  
Old 04-11-2006
strtoul.c calls strtol.c --
Code:
/* Convert string representation of a number into an integer value.
   Copyright (C) 1991,92,94,95,96,97,98,99,2000,2001,2002,2003
   	Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#if HAVE_CONFIG_H
# include <config.h>
#endif

#ifdef _LIBC
# define USE_NUMBER_GROUPING
# define STDC_HEADERS
# define HAVE_LIMITS_H
#endif

#include <ctype.h>
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#ifndef __set_errno
# define __set_errno(Val) errno = (Val)
#endif

#ifdef HAVE_LIMITS_H
# include <limits.h>
#endif

#ifdef STDC_HEADERS
# include <stddef.h>
# include <stdlib.h>
# include <string.h>
# include <locale.h>
#else
# ifndef NULL
#  define NULL 0
# endif
#endif

#ifdef USE_NUMBER_GROUPING
# include "../locale/localeinfo.h"
#endif

/* Nonzero if we are defining `strtoul' or `strtoull', operating on
   unsigned integers.  */
#ifndef UNSIGNED
# define UNSIGNED 0
# define INT LONG int
#else
# define INT unsigned LONG int
#endif

/* Determine the name.  */
#ifdef USE_IN_EXTENDED_LOCALE_MODEL
# if UNSIGNED
#  ifdef USE_WIDE_CHAR
#   ifdef QUAD
#    define strtol __wcstoull_l
#   else
#    define strtol __wcstoul_l
#   endif
#  else
#   ifdef QUAD
#    define strtol __strtoull_l
#   else
#    define strtol __strtoul_l
#   endif
#  endif
# else
#  ifdef USE_WIDE_CHAR
#   ifdef QUAD
#    define strtol __wcstoll_l
#   else
#    define strtol __wcstol_l
#   endif
#  else
#   ifdef QUAD
#    define strtol __strtoll_l
#   else
#    define strtol __strtol_l
#   endif
#  endif
# endif
#else
# if UNSIGNED
#  ifdef USE_WIDE_CHAR
#   ifdef QUAD
#    define strtol wcstoull
#   else
#    define strtol wcstoul
#   endif
#  else
#   ifdef QUAD
#    define strtol strtoull
#   else
#    define strtol strtoul
#   endif
#  endif
# else
#  ifdef USE_WIDE_CHAR
#   ifdef QUAD
#    define strtol wcstoll
#   else
#    define strtol wcstol
#   endif
#  else
#   ifdef QUAD
#    define strtol strtoll
#   endif
#  endif
# endif
#endif

/* If QUAD is defined, we are defining `strtoll' or `strtoull',
   operating on `long long int's.  */
#ifdef QUAD
# define LONG long long
# define STRTOL_LONG_MIN LONG_LONG_MIN
# define STRTOL_LONG_MAX LONG_LONG_MAX
# define STRTOL_ULONG_MAX ULONG_LONG_MAX
# if __GNUC__ == 2 && __GNUC_MINOR__ < 7
   /* Work around gcc bug with using this constant.  */
   static const unsigned long long int maxquad = ULONG_LONG_MAX;
#  undef STRTOL_ULONG_MAX
#  define STRTOL_ULONG_MAX maxquad
# endif
#else
# define LONG long

# ifndef ULONG_MAX
#  define ULONG_MAX ((unsigned long) ~(unsigned long) 0)
# endif
# ifndef LONG_MAX
#  define LONG_MAX ((long int) (ULONG_MAX >> 1))
# endif
# define STRTOL_LONG_MIN LONG_MIN
# define STRTOL_LONG_MAX LONG_MAX
# define STRTOL_ULONG_MAX ULONG_MAX
#endif


/* We use this code also for the extended locale handling where the
   function gets as an additional argument the locale which has to be
   used.  To access the values we have to redefine the _NL_CURRENT
   macro.  */
#ifdef USE_IN_EXTENDED_LOCALE_MODEL
# undef _NL_CURRENT
# define _NL_CURRENT(category, item) \
  (current->values[_NL_ITEM_INDEX (item)].string)
# define LOCALE_PARAM , loc
# define LOCALE_PARAM_DECL __locale_t loc;
#else
# define LOCALE_PARAM
# define LOCALE_PARAM_DECL
#endif

#if defined _LIBC || defined HAVE_WCHAR_H
# include <wchar.h>
#endif

#ifdef USE_WIDE_CHAR
# include <wctype.h>
# define L_(Ch) L##Ch
# define UCHAR_TYPE wint_t
# define STRING_TYPE wchar_t
# ifdef USE_IN_EXTENDED_LOCALE_MODEL
#  define ISSPACE(Ch) __iswspace_l ((Ch), loc)
#  define ISALPHA(Ch) __iswalpha_l ((Ch), loc)
#  define TOUPPER(Ch) __towupper_l ((Ch), loc)
# else
#  define ISSPACE(Ch) iswspace (Ch)
#  define ISALPHA(Ch) iswalpha (Ch)
#  define TOUPPER(Ch) towupper (Ch)
# endif
# else
#  if defined _LIBC \
   || defined STDC_HEADERS || (!defined isascii && !defined HAVE_ISASCII)
#   define IN_CTYPE_DOMAIN(c) 1
#  else
#   define IN_CTYPE_DOMAIN(c) isascii(c)
#  endif
#  define L_(Ch) Ch
#  define UCHAR_TYPE unsigned char
#  define STRING_TYPE char
# ifdef USE_IN_EXTENDED_LOCALE_MODEL
#  define ISSPACE(Ch) __isspace_l ((Ch), loc)
#  define ISALPHA(Ch) __isalpha_l ((Ch), loc)
#  define TOUPPER(Ch) __toupper_l ((Ch), loc)
# else
#  define ISSPACE(Ch) (IN_CTYPE_DOMAIN (Ch) && isspace (Ch))
#  define ISALPHA(Ch) (IN_CTYPE_DOMAIN (Ch) && isalpha (Ch))
#  define TOUPPER(Ch) (IN_CTYPE_DOMAIN (Ch) ? toupper (Ch) : (Ch))
# endif
#endif

#ifdef __STDC__
# define INTERNAL(X) INTERNAL1(X)
# define INTERNAL1(X) __##X##_internal
# define WEAKNAME(X) WEAKNAME1(X)
#else
# define INTERNAL(X) __/**/X/**/_internal
#endif

#ifdef USE_NUMBER_GROUPING
/* This file defines a function to check for correct grouping.  */
# include "grouping.h"
#endif



/* Convert NPTR to an `unsigned long int' or `long int' in base BASE.
   If BASE is 0 the base is determined by the presence of a leading
   zero, indicating octal or a leading "0x" or "0X", indicating hexadecimal.
   If BASE is < 2 or > 36, it is reset to 10.
   If ENDPTR is not NULL, a pointer to the character after the last
   one converted is stored in *ENDPTR.  */

INT
INTERNAL (strtol) (nptr, endptr, base, group LOCALE_PARAM)
     const STRING_TYPE *nptr;
     STRING_TYPE **endptr;
     int base;
     int group;
     LOCALE_PARAM_DECL
{
  int negative;
  register unsigned LONG int cutoff;
  register unsigned int cutlim;
  register unsigned LONG int i;
  register const STRING_TYPE *s;
  register UCHAR_TYPE c;
  const STRING_TYPE *save, *end;
  int overflow;
#ifndef USE_WIDE_CHAR
  size_t cnt;
#endif

#ifdef USE_NUMBER_GROUPING
# ifdef USE_IN_EXTENDED_LOCALE_MODEL
  struct locale_data *current = loc->__locales[LC_NUMERIC];
# endif
  /* The thousands character of the current locale.  */
# ifdef USE_WIDE_CHAR
  wchar_t thousands = L'\0';
# else
  const char *thousands = NULL;
  size_t thousands_len = 0;
# endif
  /* The numeric grouping specification of the current locale,
     in the format described in <locale.h>.  */
  const char *grouping;

  if (__builtin_expect (group, 0))
    {
      grouping = _NL_CURRENT (LC_NUMERIC, GROUPING);
      if (*grouping <= 0 || *grouping == CHAR_MAX)
	grouping = NULL;
      else
	{
	  /* Figure out the thousands separator character.  */
# ifdef USE_WIDE_CHAR
#  ifdef _LIBC
	  thousands = _NL_CURRENT_WORD (LC_NUMERIC,
					_NL_NUMERIC_THOUSANDS_SEP_WC);
#  endif
	  if (thousands == L'\0')
	    grouping = NULL;
# else
#  ifdef _LIBC
	  thousands = _NL_CURRENT (LC_NUMERIC, THOUSANDS_SEP);
#  endif
	  if (*thousands == '\0')
	    {
	      thousands = NULL;
	      grouping = NULL;
	    }
# endif
	}
    }
  else
    grouping = NULL;
#endif

  if (base < 0 || base == 1 || base > 36)
    {
      __set_errno (EINVAL);
      return 0;
    }

  save = s = nptr;

  /* Skip white space.  */
  while (ISSPACE (*s))
    ++s;
  if (__builtin_expect (*s == L_('\0'), 0))
    goto noconv;

  /* Check for a sign.  */
  negative = 0;
  if (*s == L_('-'))
    {
      negative = 1;
      ++s;
    }
  else if (*s == L_('+'))
    ++s;

  /* Recognize number prefix and if BASE is zero, figure it out ourselves.  */
  if (*s == L_('0'))
    {
      if ((base == 0 || base == 16) && TOUPPER (s[1]) == L_('X'))
	{
	  s += 2;
	  base = 16;
	}
      else if (base == 0)
	base = 8;
    }
  else if (base == 0)
    base = 10;

  /* Save the pointer so we can check later if anything happened.  */
  save = s;

#ifdef USE_NUMBER_GROUPING
  if (base != 10)
    grouping = NULL;

  if (__builtin_expect (grouping != NULL, 0))
    {
# ifndef USE_WIDE_CHAR
      thousands_len = strlen (thousands);
# endif

      /* Find the end of the digit string and check its grouping.  */
      end = s;
      if (
# ifdef USE_WIDE_CHAR
	  *s != thousands
# else
	  ({ for (cnt = 0; cnt < thousands_len; ++cnt)
	       if (thousands[cnt] != end[cnt])
		 break;
	     cnt < thousands_len; })
# endif
	  )
	{
	  for (c = *end; c != L_('\0'); c = *++end)
	    if (((STRING_TYPE) c < L_('0') || (STRING_TYPE) c > L_('9'))
# ifdef USE_WIDE_CHAR
		&& (wchar_t) c != thousands
# else
		&& ({ for (cnt = 0; cnt < thousands_len; ++cnt)
		      if (thousands[cnt] != end[cnt])
			break;
		      cnt < thousands_len; })
# endif
		&& (!ISALPHA (c)
		    || (int) (TOUPPER (c) - L_('A') + 10) >= base))
	      break;

# ifdef USE_WIDE_CHAR
	  end = __correctly_grouped_prefixwc (s, end, thousands, grouping);
# else
	  end = __correctly_grouped_prefixmb (s, end, thousands, grouping);
# endif
	}
    }
  else
#endif
    end = NULL;

  cutoff = STRTOL_ULONG_MAX / (unsigned LONG int) base;
  cutlim = STRTOL_ULONG_MAX % (unsigned LONG int) base;

  overflow = 0;
  i = 0;
  c = *s;
  if (sizeof (long int) != sizeof (LONG int))
    {
      unsigned long int j = 0;
      unsigned long int jmax = ULONG_MAX / base;

      for (;c != L_('\0'); c = *++s)
	{
	  if (s == end)
	    break;
	  if (c >= L_('0') && c <= L_('9'))
	    c -= L_('0');
#ifdef USE_NUMBER_GROUPING
# ifdef USE_WIDE_CHAR
	  else if (grouping && (wchar_t) c == thousands)
	    continue;
# else
	  else if (thousands_len)
	    {
	      for (cnt = 0; cnt < thousands_len; ++cnt)
		if (thousands[cnt] != s[cnt])
		  break;
	      if (cnt == thousands_len)
		{
		  s += thousands_len - 1;
		  continue;
		}
	      if (ISALPHA (c))
		c = TOUPPER (c) - L_('A') + 10;
	      else
		break;
	    }
# endif
#endif
	  else if (ISALPHA (c))
	    c = TOUPPER (c) - L_('A') + 10;
	  else
	    break;
	  if ((int) c >= base)
	    break;
	  /* Note that we never can have an overflow.  */
	  else if (j >= jmax)
	    {
	      /* We have an overflow.  Now use the long representation.  */
	      i = (unsigned LONG int) j;
	      goto use_long;
	    }
	  else
	    j = j * (unsigned long int) base + c;
	}

      i = (unsigned LONG int) j;
    }
  else
    for (;c != L_('\0'); c = *++s)
      {
	if (s == end)
	  break;
	if (c >= L_('0') && c <= L_('9'))
	  c -= L_('0');
#ifdef USE_NUMBER_GROUPING
# ifdef USE_WIDE_CHAR
	else if (grouping && (wchar_t) c == thousands)
	  continue;
# else
	else if (thousands_len)
	  {
	    for (cnt = 0; cnt < thousands_len; ++cnt)
	      if (thousands[cnt] != s[cnt])
		break;
	    if (cnt == thousands_len)
	      {
		s += thousands_len - 1;
		continue;
	      }
	    if (ISALPHA (c))
	      c = TOUPPER (c) - L_('A') + 10;
	    else
	      break;
	  }
# endif
#endif
	else if (ISALPHA (c))
	  c = TOUPPER (c) - L_('A') + 10;
	else
	  break;
	if ((int) c >= base)
	  break;
	/* Check for overflow.  */
	if (i > cutoff || (i == cutoff && c > cutlim))
	  overflow = 1;
	else
	  {
	  use_long:
	    i *= (unsigned LONG int) base;
	    i += c;
	  }
      }

  /* Check if anything actually happened.  */
  if (s == save)
    goto noconv;

  /* Store in ENDPTR the address of one character
     past the last character we converted.  */
  if (endptr != NULL)
    *endptr = (STRING_TYPE *) s;

#if !UNSIGNED
  /* Check for a value that is within the range of
     `unsigned LONG int', but outside the range of `LONG int'.  */
  if (overflow == 0
      && i > (negative
	      ? -((unsigned LONG int) (STRTOL_LONG_MIN + 1)) + 1
	      : (unsigned LONG int) STRTOL_LONG_MAX))
    overflow = 1;
#endif

  if (__builtin_expect (overflow, 0))
    {
      __set_errno (ERANGE);
#if UNSIGNED
      return STRTOL_ULONG_MAX;
#else
      return negative ? STRTOL_LONG_MIN : STRTOL_LONG_MAX;
#endif
    }

  /* Return the result of the appropriate sign.  */
  return negative ? -i : i;

noconv:
  /* We must handle a special case here: the base is 0 or 16 and the
     first two characters are '0' and 'x', but the rest are no
     hexadecimal digits.  This is no error case.  We return 0 and
     ENDPTR points to the `x`.  */
  if (endptr != NULL)
    {
      if (save - nptr >= 2 && TOUPPER (save[-1]) == L_('X')
	  && save[-2] == L_('0'))
	*endptr = (STRING_TYPE *) &save[-1];
      else
	/*  There was no number to convert.  */
	*endptr = (STRING_TYPE *) nptr;
    }

  return 0L;
}
#if defined _LIBC \
    && !(defined USE_IN_EXTENDED_LOCALE_MODEL && defined USE_WIDE_CHAR)
libc_hidden_def (INTERNAL (strtol))
#endif

/* External user entry point.  */

#if _LIBC - 0 == 0
# undef PARAMS
# if defined (__STDC__) && __STDC__
#  define PARAMS(Args) Args
# else
#  define PARAMS(Args) ()
# endif

/* Prototype.  */
INT strtol PARAMS ((const STRING_TYPE *nptr, STRING_TYPE **endptr, int base));
#endif


INT
#ifdef weak_function
weak_function
#endif
strtol (nptr, endptr, base LOCALE_PARAM)
     const STRING_TYPE *nptr;
     STRING_TYPE **endptr;
     int base;
     LOCALE_PARAM_DECL
{
  return INTERNAL (strtol) (nptr, endptr, base, 0 LOCALE_PARAM);
}

# 4  
Old 04-12-2006
Thanking you kindly

Great thanks. The answer was a little more complicated than I expected. I've found the libraries, and located the lines in the ATOI function that I needed.
 
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Source code

hii... i am a biginner....and i have linux source code ,downloaded from some website ,a compressed file on windows and dont know how do compile them..... (4 Replies)
Discussion started by: M K Raju
4 Replies

2. Linux

Source code

I need the source code of fedora. plz plz plz help me........... (1 Reply)
Discussion started by: neh
1 Replies

3. Shell Programming and Scripting

Block of code replacement in Java source code through Unix script

Hi, I want to remove the following code from Source files (or replace the code with empty.) from all the source files in given directory. finally { if (null != hibernateSession && hibernateSession.isOpen()) { //hibernateSession.close(); } } It would be great if the script has... (2 Replies)
Discussion started by: hareeshram
2 Replies

4. UNIX for Dummies Questions & Answers

Where can i get unix source code?

Sir please tell me where can i get source code for some unix kernal and shell also. (1 Reply)
Discussion started by: VIPUL15
1 Replies

5. Shell Programming and Scripting

Linux source code

Unix is written in C. From where u can see the source code of unix or linux (1 Reply)
Discussion started by: pritish.sas
1 Replies

6. Linux

source code for linux

Hi , where can i get free source code for LINUX commands , OS , system calls etc. Thanks Naren (2 Replies)
Discussion started by: naren_chella
2 Replies

7. UNIX for Dummies Questions & Answers

source code download

hai This is A.gowri kumar from india.I am very facinated with this operating system. so i want to download the whole source code of this operating system (UNIX). So from where can i Download the source code. Please help me. (1 Reply)
Discussion started by: tapanagkumar
1 Replies

8. Programming

vmstat source code

i am looking for vmstat source code or a listing of the kernel symbols that vmstat uses in the knlist subroutine. Interested in getting vmstat stats from a c program using knlist subroutine, but i dont know what the names of the kernel symbols are that i need to access. thanks in advance::) (2 Replies)
Discussion started by: briansmith40
2 Replies

9. UNIX for Dummies Questions & Answers

SCCS (Source Code)

Hello, I'm wondering if anyone out there have experience using the SCCS source code in Unix? If so, can you recommend a good (user friendly) SCCS book for beginner users. Thanks! (3 Replies)
Discussion started by: Mary
3 Replies
Login or Register to Ask a Question