diff options
Diffstat (limited to 'Documentation/technical/api-run-command.txt')
| -rw-r--r-- | Documentation/technical/api-run-command.txt | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/Documentation/technical/api-run-command.txt b/Documentation/technical/api-run-command.txt index f18b4f4817..8bf3e37f53 100644 --- a/Documentation/technical/api-run-command.txt +++ b/Documentation/technical/api-run-command.txt @@ -13,6 +13,10 @@ produces in the caller in order to process it. Functions --------- +`child_process_init`:: + + Initialize a struct child_process variable. + `start_command`:: Start a sub-process. Takes a pointer to a `struct child_process` @@ -42,6 +46,13 @@ Functions The argument dir corresponds the member .dir. The argument env corresponds to the member .env. +`child_process_clear`:: + + Release the memory associated with the struct child_process. + Most users of the run-command API don't need to call this + function explicitly because `start_command` invokes it on + failure and `finish_command` calls it automatically already. + The functions above do the following: . If a system call failed, errno is set and -1 is returned. A diagnostic @@ -55,10 +66,8 @@ The functions above do the following: non-zero. . If the program terminated due to a signal, then the return value is the - signal number - 128, ie. it is negative and so indicates an unusual - condition; a diagnostic is printed. This return value can be passed to - exit(2), which will report the same code to the parent process that a - POSIX shell's $? would report for a program that died from the signal. + signal number + 128, ie. the same value that a POSIX shell's $? would + report. A diagnostic is printed. `start_async`:: @@ -98,8 +107,8 @@ command to run in a sub-process. The caller: -1. allocates and clears (memset(&chld, 0, sizeof(chld));) a - struct child_process variable; +1. allocates and clears (using child_process_init() or + CHILD_PROCESS_INIT) a struct child_process variable; 2. initializes the members; 3. calls start_command(); 4. processes the data; @@ -111,6 +120,13 @@ terminated), of which .argv[0] is the program name to run (usually without a path). If the command to run is a git command, set argv[0] to the command name without the 'git-' prefix and set .git_cmd = 1. +Note that the ownership of the memory pointed to by .argv stays with the +caller, but it should survive until `finish_command` completes. If the +.argv member is NULL, `start_command` will point it at the .args +`argv_array` (so you may use one or the other, but you must use exactly +one). The memory in .args will be cleaned up automatically during +`finish_command` (or during `start_command` when it is unsuccessful). + The members .in, .out, .err are used to redirect stdin, stdout, stderr as follows: @@ -160,6 +176,11 @@ string pointers (NULL terminated) in .env: . If the string does not contain '=', it names an environment variable that will be removed from the child process's environment. +If the .env member is NULL, `start_command` will point it at the +.env_array `argv_array` (so you may use one or the other, but not both). +The memory in .env_array will be cleaned up automatically during +`finish_command` (or during `start_command` when it is unsuccessful). + To specify a new initial working directory for the sub-process, specify it in the .dir member. |