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execv |
Portability: | POSIX.1 conforming, UNIX compatible |
SYNOPSIS | |
DESCRIPTION | |
RETURN VALUE | |
EXAMPLE | |
RELATED FUNCTIONS |
SYNOPSIS |
#include <unistd.h> int execv(const char *file, char *const argv[]);
DESCRIPTION |
Like all of the
exec
functions,
execv
replaces the calling process image with a new process image.
This has the effect of running a new progam with the process ID of the calling
process. Note that a new process is not started; the new process image simply
overlays the original process image. The
execv
function is most commonly used to overlay a process image that
has been created by a call to the
fork
function.
file
argv
NULL
pointer is used to mark the end of the array. Each character string
pointed to by the array is used to pass an argument to the new process image.
The first argument,
argv[0]
,
is required and must contain the name of the executable file for the new process
image.
RETURN VALUE |
A successful call to
execv
does not have a return value because the
new process image overlays the calling process image. However, a
-1
is returned if the call to
execv
is unsuccessful.
EXAMPLE |
The following example illustrates the
use of
execv
to execute
the
ls
shell command:
#include <sys/types.h> #include <unistd.h> #include <stdio.h> main() { pid_t pid; char *const parmList[] = {"/bin/ls", "-l", "/u/userid/dirname", NULL}; if ((pid = fork()) == -1) perror("fork error"); else if (pid == 0) { execv("/bin/ls", parmList); printf("Return not expected. Must be an execv error.\n"); } }
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