execvp

execvp is a function in the POSIX C library used to replace the current process image with a new program. It is part of the exec family of functions. The prototype is int execvp(const char *file, char *const argv[]); The argv array must be terminated by a NULL pointer, and argv[0] is conventionally the name of the program being executed.

execvp searches for the specified file in the directories listed in the PATH environment variable, unless the file name contains a slash, in which case PATH is not searched and the file is attempted directly. If a suitable executable is found and loaded, the current process image is replaced by the new program and control does not return to the caller. If execution fails, the function returns -1 and errno is set to indicate the error (examples include ENOENT for a missing file, EACCES for permission denied, ENOEXEC for an invalid executable format).

The environment of the new program is inherited from the calling process. It does not take an explicit environment parameter. To supply a custom environment, one would use a variant such as execve (which accepts an envp argument) or platform-specific variants like execvpe that combine PATH search with a custom environment.

Typical usage involves forking a process and calling execvp in the child to run a different program while allowing the parent to continue or terminate independently.

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