add READMEgetprogname

1 files changed, 36 insertions, 0 deletions

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..d445efb
--- /dev/null
+++ b/README.md
@@ -0,0 +1,36 @@
+getprogname
+===========
+
+This liblet includes two functions, `getprogname()` and `get_program_name()`.
+The former is an implementation of the BSD function of the same name. The
+latter is a variant that takes a buffer to fill along with its size as
+arguments, rather than relying on a static variable. This makes it thread safe.
+
+SYNOPSIS
+========
+
+    #include "getprogname.h"
+
+    char *get_program_name(size_t n, char buf[static n]);
+    char *getprogname(void);
+
+DESCRIPTION
+===========
+
+These functions provide the current process's name as derived from the original
+contents of `argv[0]`.
+
+`getprogname()` returns a pointer to a static buffer, which may overwritten by
+future calls to `getprogname()`.
+
+`get_program_name()` will fill the buffer pointed to by `buf`, up to `n` bytes,
+with the current process name. The declaration syntax requires a compiler
+supporting at least C99, and allows the compiler to perform static analysis
+on the size of `buf` to ensure that it is at least `n` bytes in size.
+
+RETURN VALUE
+============
+
+On failure, both functions return `NULL`. On success, `getprogname()` returns
+a pointer to a static buffer containing the current program name;
+`get_program_name()` returns a pointer to `buf`.