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A computer operating system loads an executable file into a call stack on a hard disk.
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asprintf(3) [bsd man page]

ASPRINTF(3)						     Linux Programmer's Manual						       ASPRINTF(3)

NAME
asprintf, vasprintf - print to allocated string SYNOPSIS
#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <stdio.h> int asprintf(char **strp, const char *fmt, ...); int vasprintf(char **strp, const char *fmt, va_list ap); DESCRIPTION
The functions asprintf() and vasprintf() are analogs of sprintf(3) and vsprintf(3), except that they allocate a string large enough to hold the output including the terminating null byte (''), and return a pointer to it via the first argument. This pointer should be passed to free(3) to release the allocated storage when it is no longer needed. RETURN VALUE
When successful, these functions return the number of bytes printed, just like sprintf(3). If memory allocation wasn't possible, or some other error occurs, these functions will return -1, and the contents of strp are undefined. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +------------------------+---------------+----------------+ |Interface | Attribute | Value | +------------------------+---------------+----------------+ |asprintf(), vasprintf() | Thread safety | MT-Safe locale | +------------------------+---------------+----------------+ CONFORMING TO
These functions are GNU extensions, not in C or POSIX. They are also available under *BSD. The FreeBSD implementation sets strp to NULL on error. SEE ALSO
free(3), malloc(3), printf(3) COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. GNU
2017-09-15 ASPRINTF(3)

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STRDUP(3)						     Linux Programmer's Manual							 STRDUP(3)

NAME
strdup, strndup, strdupa, strndupa - duplicate a string SYNOPSIS
#include <string.h> char *strdup(const char *s); char *strndup(const char *s, size_t n); char *strdupa(const char *s); char *strndupa(const char *s, size_t n); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): strdup(): _XOPEN_SOURCE >= 500 || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE strndup(): Since glibc 2.10: _POSIX_C_SOURCE >= 200809L Before glibc 2.10: _GNU_SOURCE strdupa(), strndupa(): _GNU_SOURCE DESCRIPTION
The strdup() function returns a pointer to a new string which is a duplicate of the string s. Memory for the new string is obtained with malloc(3), and can be freed with free(3). The strndup() function is similar, but copies at most n bytes. If s is longer than n, only n bytes are copied, and a terminating null byte ('') is added. strdupa() and strndupa() are similar, but use alloca(3) to allocate the buffer. They are available only when using the GNU GCC suite, and suffer from the same limitations described in alloca(3). RETURN VALUE
On success, the strdup() function returns a pointer to the duplicated string. It returns NULL if insufficient memory was available, with errno set to indicate the cause of the error. ERRORS
ENOMEM Insufficient memory available to allocate duplicate string. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +--------------------------------+---------------+---------+ |Interface | Attribute | Value | +--------------------------------+---------------+---------+ |strdup(), strndup(), strdupa(), | Thread safety | MT-Safe | |strndupa() | | | +--------------------------------+---------------+---------+ CONFORMING TO
strdup() conforms to SVr4, 4.3BSD, POSIX.1-2001. strndup() conforms to POSIX.1-2008. strdupa() and strndupa() are GNU extensions. SEE ALSO
alloca(3), calloc(3), free(3), malloc(3), realloc(3), string(3), wcsdup(3) COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. GNU
2017-09-15 STRDUP(3)

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