1EXEC(3) Linux Programmer's Manual EXEC(3)
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6 execl, execlp, execle, execv, execvp, execvpe - execute a file
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9 #include <unistd.h>
10 extern char **environ;
12 int execl(const char *pathname, const char *arg, ...
14 /* (char *) NULL */);
15 int execlp(const char *file, const char *arg, ...
16 /* (char *) NULL */);
17 int execle(const char *pathname, const char *arg, ...
18 /*, (char *) NULL, char *const envp[] */);
19 int execv(const char *pathname, char *const argv[]);
20 int execvp(const char *file, char *const argv[]);
21 int execvpe(const char *file, char *const argv[],
22 char *const envp[]);
23 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
25 execvpe(): _GNU_SOURCE
27
29 The exec() family of functions replaces the current process image with
30 a new process image. The functions described in this manual page are
31 layered on top of execve(2). (See the manual page for execve(2) for
32 further details about the replacement of the current process image.)
33 The initial argument for these functions is the name of a file that is
35 to be executed.
36 The functions can be grouped based on the letters following the "exec"
38 prefix.
39 l - execl(), execlp(), execle()
41 The const char *arg and subsequent ellipses can be thought of as arg0,
42 arg1, ..., argn. Together they describe a list of one or more pointers
43 to null-terminated strings that represent the argument list available
44 to the executed program. The first argument, by convention, should
45 point to the filename associated with the file being executed. The
46 list of arguments must be terminated by a null pointer, and, since
47 these are variadic functions, this pointer must be cast (char *) NULL.
48 By contrast with the 'l' functions, the 'v' functions (below) specify
50 the command-line arguments of the executed program as a vector.
51 v - execv(), execvp(), execvpe()
53 The char *const argv[] argument is an array of pointers to null-termi‐
54 nated strings that represent the argument list available to the new
55 program. The first argument, by convention, should point to the file‐
56 name associated with the file being executed. The array of pointers
57 must be terminated by a null pointer.
58 e - execle(), execvpe()
60 The environment of the caller is specified via the argument envp. The
61 envp argument is an array of pointers to null-terminated strings and
62 must be terminated by a null pointer.
63 All other exec() functions (which do not include 'e' in the suffix)
65 take the environment for the new process image from the external vari‐
66 able environ in the calling process.
67 p - execlp(), execvp(), execvpe()
69 These functions duplicate the actions of the shell in searching for an
70 executable file if the specified filename does not contain a slash (/)
71 character. The file is sought in the colon-separated list of directory
72 pathnames specified in the PATH environment variable. If this variable
73 isn't defined,