01-24-2006
The exec family of functions can only be used to execute files from within a program. You seem to want to execute a shell function instead. I am afraid you cannot do that.
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1. Programming
Hi,
Is it possible to run a program from my C program using only the full pathname?
for example if I wanna call: "ls", so I whould have to use:
execl("/bin/ls", "ls", NULL);
Is it possible to do this using only:
"/bin/ls"
thanks (1 Reply)
Discussion started by: owijust
1 Replies
2. Programming
can anyone explain how to pass arguments of a program in execl function
pls explain with a sample code. (2 Replies)
Discussion started by: bankpro
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3. Shell Programming and Scripting
I want to make simultanous sh commands in an exec command
for example I want to counts the lines in a file
wc -l my file.txt | awk -F" " '{print $1}'` works fine in sh but I want to implement it in a c code
the first part works like this
execl("/usr/bin/wc", "wc", "-l", "myfile.txt",... (1 Reply)
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4. Programming
Hi,
we would appreciate if any one answer the below query.
void main()
{
printf(“ I am in main\n”);
execl(“/HOME/source/file2”,” /HOME/source/file2”,1,0);
printf(“after execl\n”);
}
How to step the file2 source code in GDB. (2 Replies)
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5. Programming
hello everybody
how can i time the execution of execl() command inside my C code?
for example, i wrote..
execl("md5sum","md5sum","myprog",NULL);
i want to count the duration of the execl command!
thanx in advance! (2 Replies)
Discussion started by: nicos
2 Replies
6. Red Hat
how to use find command in execl function,
I used:
execl("/usr/bin/find","find","~","-name","filename.c",0); but it shows
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7. Programming
when execl fails using the command lss, it doesnt go into the next line
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perror("execl failed"); exit(127);
for some reason the child process just stops and also the parent process also stops
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8. Programming
Hi, I have two programs, one is named "Master" and the other one "slave". What I want to do is , when I execute Master, inside slave will be called by excecl, do some calculations, and send those to the master program... A little example of what I am failing to do:
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Hello,
From the URL
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10. UNIX for Beginners Questions & Answers
Hi,
If I write in a c file :
execlp("date","date",NULL);
printf("A\n");
And then run through the terminal would "A" be printed ?
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Discussion started by: uniran
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varargs(3EXT) Extended Library Functions varargs(3EXT)
NAME
varargs - handle variable argument list
SYNOPSIS
#include <varargs.h>
va_alist
va_dcl
va_list pvar;
void va_start(va_listpvar);
type va_arg(va_list pvar, type);
void va_end(va_list pvar);
DESCRIPTION
This set of macros allows portable procedures that accept variable argument lists to be written. Routines that have variable argument lists
(such as printf(3C)) but do not use varargs are inherently non-portable, as different machines use different argument-passing conventions.
va_alist is used as the parameter list in a function header.
va_dcl is a declaration for va_alist. No semicolon should follow va_dcl.
va_list is a type defined for the variable used to traverse the list.
va_start is called to initialize pvar to the beginning of the list.
va_arg will return the next argument in the list pointed to by pvar. type is the type the argument is expected to be. Different types can
be mixed, but it is up to the routine to know what type of argument is expected, as it cannot be determined at runtime.
va_end is used to clean up.
Multiple traversals, each bracketed by va_start and va_end, are possible.
EXAMPLES
Example 1: A sample program.
This example is a possible implementation of execl (see exec(2) ).
#include <unistd.h>
#include <varargs.h>
#define MAXARGS 100
/* execl is called by
execl(file, arg1, arg2, ..., (char *)0);
*/
execl(va_alist)
va_dcl
{
va_list ap;
char *file;
char *args[MAXARGS]; /* assumed big enough*/
int argno = 0;
va_start(ap);
file = va_arg(ap, char *);
while ((args[argno++] = va_arg(ap, char *)) != 0)
;
va_end(ap);
return execv(file, args);
}
SEE ALSO
exec(2), printf(3C), vprintf(3C), stdarg(3EXT)
NOTES
It is up to the calling routine to specify in some manner how many arguments there are, since it is not always possible to determine the
number of arguments from the stack frame. For example, execl is passed a zero pointer to signal the end of the list. printf can tell how
many arguments are there by the format.
It is non-portable to specify a second argument of char, short, or float to va_arg, since arguments seen by the called function are not
char, short, or float. C converts char and short arguments to int and converts float arguments to double before passing them to a function.
stdarg is the preferred interface.
SunOS 5.10 10 May 2002 varargs(3EXT)