1. 包含getopt.h
2. 定义短选项，比如，ho:v
3. 定义长选项结构，注意最后一项全部设为0
4. 未定义的选项，解析时会返回’?’
5. 含有参数的选项，参数存于全局变量optarg中
6. 非参数选项的起始索引，存于全局变量optind中
示例程序如下：
#include <stdio.h></stdio.h>
#include <getopt.h></getopt.h>
const char* program_name;
void print_usage(FILE* stream, int exit_code){
fprintf(stream, "Usage: %s options [ inputfile ...]n", program_name);
fprintf(stream, " -h –help Display this uage information.n"
" -v –verbose Print verbose message.n"
" -o –output filename Write output to file.n");
exit(exit_code);
}
int main(int argc, char* argv[]){
int next_option;
const char* short_options = "ho:v";
const struct option long_options[] = {
{"help", 0, NULL, ‘h’},
{"output", 1, NULL, ‘o’},
{"verbose", 0, NULL, ‘v’},
{NULL, 0, NULL, 0}
};
const char* output_filename = NULL;
int verbose = 0;
program_name = argv[0];
do{
next_option = getopt_long(argc, argv, short_options, long_options, NULL);
switch(next_option){
case ‘h’:
print_usage(stdout, 0);
case ‘o’:
//the global var optarg contains the specified argument
output_filename = optarg;
break;
case ‘v’:
verbose = 1;
break;
case ‘?’: //if the arg list contains invalid options
print_usage(stderr, 1);
case -1:
break;
default:
abort();
}
}while(next_option != -1);
printf("[option] verbose: %dn", verbose);
printf("[option] output: %sn", output_filename);
if(verbose){
int i;
//the global var optind contains the index of the first nonoption argument
for(i = optind; i<argc;></argc;> printf("Argument: %sn", argv[i]);
}
}
return 0;
}
相应的Makefile：
CFLAGS=-Wall -g
all: getopt
getopt: getopt.o
$(CC) $(CFLAGS) -o $@ $@.o
%.o: %.c
$(CC) $(CFLAGS) -c $+
clean:
rm -f *.o
rm -f getopt
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