mongoose/docs/c-api/mg_http_server.h/mg_get_http_var.md

title	decl_name	symbol_kind	signature
mg_get_http_var()	mg_get_http_var	func	int mg_get_http_var(const struct mg_str *buf, const char *name, char *dst, size_t dst_len);

Fetches a HTTP form variable.

Fetches a variable name from a buf into a buffer specified by dst, dst_len. The destination is always zero-terminated. Returns the length of a fetched variable. If not found, 0 is returned. buf must be valid url-encoded buffer. If destination is too small or an error occured, negative number is returned.