XXX Add argp_parse() call to main() and build it

minimal-argp-parse.c

@@ -0,0 +1,6 @@
+#include <argp.h>
+
+int main(int argc, char *argv[]) {
+  error_t e = argp_parse(NULL, argc, argv, 0, NULL, NULL);
+  return (e != 0) ? 0 : 1;
+}

src/Makefile.am

@@ -236,6 +236,12 @@ avrdude_SOURCES = \
 	developer_opts.h \
 	developer_opts_private.h
 
+if REQUIRE_ARGP_SOURCES
+avrdude_CPPFLAGS += -I$(srcdir)/gnulib
+avrdude_SOURCES  += gnulib/argp.h
+avrdude_SOURCES  += gnulib/argp-parse.c
+endif
+
 dist_bin_SCRIPTS = elf2tag
 
 man_MANS = avrdude.1

src/configure.ac

@@ -172,6 +172,28 @@ dnl Makefile.am:77: compiling `config_gram.c' with per-target flags requires `AM
 AM_PROG_CC_C_O
 
 # Checks for libraries.
+
+# Check whether the argp API (argp_parse() etc.) is available out of
+# the box or whether we need to compile and link against
+# `gnulib/argp*.c`.
+AC_MSG_CHECKING([whether compile and link works for argp_parse() etc])
+AC_LINK_IFELSE([AC_LANG_SOURCE([[
+#include <argp.h>
+
+int main(int argc, char *argv[]) {
+  error_t e = argp_parse(NULL, argc, argv, 0, NULL, NULL);
+  return (e != 0) ? 0 : 1;
+}
+]])], [dnl
+  AC_MSG_RESULT([yes])
+  avrdude_require_argp_sources=no
+], [dnl
+  AC_MSG_RESULT([no])
+  avrdude_require_argp_sources=yes
+])
+AM_CONDITIONAL([REQUIRE_ARGP_SOURCES],
+               [test "x$avrdude_require_argp_sources" = xyes])
+
 # For MinGW.
 AC_CHECK_LIB([ws2_32], [WSAStartup])
 

src/main.c

@@ -48,6 +48,8 @@
 #include <dirent.h>
 #endif
 
+#include <argp.h>
+
 #include "avrdude.h"
 #include "libavrdude.h"
 #include "config.h"
@@ -813,6 +815,11 @@ int main(int argc, char *argv[]) {
     concatpath(usr_config, getenv("HOME"), USER_CONF_FILE, sizeof usr_config);
 #endif
 
+  if (0 == 0) {
+    error_t err = argp_parse(NULL, argc, argv, 0, NULL, NULL);
+    printf("argp_parse() == %d\n", err);
+  }
+
   // Process command line arguments
   while((ch = getopt(argc, argv, "?Ab:B:c:C:DeE:Fi:l:nNp:OP:qrtT:U:vVx:")) != -1) {
     switch(ch) {

test-argp-parse.c

@@ -0,0 +1,108 @@
+#include <argp.h>
+#include <assert.h>
+#include <stdbool.h>
+
+const char *argp_program_version = "test-argp-parse 1.0";
+
+const char *argp_program_bug_address = "<[email protected]>";
+
+/* Program documentation. */
+static char doc[] =
+    "test-argp-parse -- Test the argp API with features useful for us.";
+
+static const struct argp_option options[] = {
+    {"flag", 'f', NULL, 0, "Set the flag", 0},
+    {"include", 'I', "DIR", 0, "Look for include files in DIR", 0},
+    {NULL, 0, NULL, 0, NULL, 0}};
+
+struct cli_arguments {
+  bool flag;
+  char *include_dir;
+};
+
+void print_cli_arguments(const struct cli_arguments *const cli) {
+  printf("CLI arguments @%p:\n", (void *)cli);
+  printf("  * include_dir: %s\n", cli->include_dir);
+}
+
+static error_t parse_opt(int key, char *arg, struct argp_state *state) {
+  assert(state != NULL);
+  struct cli_arguments *cli = state->input;
+  assert(cli != NULL);
+  switch (key) {
+
+  case 'f':
+    cli->flag = true;
+    break;
+
+  case 'I':
+    cli->include_dir = arg;
+    break;
+
+  default:
+    return ARGP_ERR_UNKNOWN;
+  }
+
+  return 0;
+}
+
+/* Our argument parser.  The options, parser, and
+   args_doc fields are zero because we have neither options or
+   arguments; doc and argp_program_bug_address will be
+   used in the output for ‘--help’, and the ‘--version’
+   option will print out argp_program_version. */
+static struct argp argp = {
+    options,   /* argp_options */
+    parse_opt, /* arg_parser_t parser function */
+    NULL,      /* argp_doc aka usage lines */
+    doc,       /* doc */
+    NULL,      /* argp_child children */
+    NULL,      /* help_filter function */
+    NULL,      /* argp_domain for translations */
+};
+
+int main(int argc, char *argv[]) {
+  printf("Original command line rguments:\n");
+  for (int i = 0; i < argc; i++) {
+    printf("  %d. %s\n", i, argv[i]);
+  }
+
+  struct cli_arguments cli = {false, NULL};
+
+  int first_unparsed = 0;
+  error_t ap_err = argp_parse(&argp, argc, argv, 0, &first_unparsed, &cli);
+
+  if (ap_err != 0) {
+    switch (ap_err) {
+    case EINVAL:
+      fprintf(stderr, "Error: Invalid command line found trying to parse the "
+                      "command line.\n");
+      return 2;
+    case ENOMEM:
+      fprintf(stderr, "Error: Not enough memory to parse the command line.\n");
+      return 2;
+    default:
+      fprintf(stderr,
+              "Error: Unknown error %d trying to parse the command line.\n",
+              ap_err);
+      return 2;
+    }
+  }
+
+  printf("Reordered command line rguments after calling argp_parse():\n");
+  for (int i = 0; i < argc; i++) {
+    printf("  %d. %s\n", i, argv[i]);
+  }
+
+  print_cli_arguments(&cli);
+
+  printf("first_unparsed: %d\n", first_unparsed);
+  if (first_unparsed < argc) {
+    printf("Unparsed CLI arguments:\n");
+    for (int i = first_unparsed; i < argc; ++i) {
+      printf("  %d. %s\n", i, argv[i]);
+    }
+  }
+
+  return 0;
+}