服务器评测
或许是我见得少，反正这是目前遇到最好命令行参数例子，下面给出源码及简单介绍：
第一部分：主要是声明一个结构体，将解析到的参数放在结构体中，同时还给出一个默认参数；
16 #include <getopt.h>
61 typedef struct Args {
62 VideoStd_Type videoStd;
63 Char *videoStdString;
64 Sound_Input soundInput;
65 Capture_Input videoInput;
66 Char *speechFile;
67 Char *videoFile;
68 Codec *speechEncoder;
69 Codec *videoEncoder;
70 Int32 imageWidth;
71 Int32 imageHeight;
72 Int videoBitRate;
73 Int keyboard;
74 Int time;
75 Int osd;
76 Int interface;
77 } Args;
78
79 #define DEFAULT_ARGS \
80 { VideoStd_D1_NTSC, “D1 NTSC”, Sound_Input_MIC, Capture_Input_COMPOSITE, \
81 NULL, NULL, NULL, NULL, 0, 0, -1, FALSE, FOREVER, FALSE, FALSE }
第二部分：核心部分，标准的信息打印，和命令行参数解析函数
118 /******************************************************************************
119 * usage
120 ******************************************************************************/
121 static void usage(void)
122 {
123 fprintf(stderr, “Usage: encode [options]\n\n”
124 “Options:\n”
125 “-s | –speechfile Speech file to record to\n”
126 “-v | –videofile Video file to record to\n”
127 “-y | –display_standard Video standard to use for display (see below).\n”
128 “-r | –resolution Video resolution (‘width’x’height’)\n”
129 ” \n”
130 “-b | –videobitrate Bit rate to encode video at [variable]\n”
131 “-x | –svideo Use s-video instead of composite video \n”
132 ” input [off]\n”
133 “-l | –linein Use linein for encoding sound instead of mic \n”
134 ” [off]\n”
135 “-k | –keyboard Enable keyboard interface [off]\n”
136 “-t | –time Number of seconds to run the demo [infinite]\n”
137 “-o | –osd Show demo data on an OSD [off]\n”
138 “-i | –interface Launch the demo interface when exiting [off]\n”
139 “-h | –help Print this message\n\n”
140 “Video standards available:\n”
141 “\t1\tD1 @ 30 fps (NTSC) [Default]\n”
142 “\t2\tD1 @ 25 fps (PAL)\n”
143 “\t3\t720P @ 60 fps\n”
144 “\t4\t720P @ 50 fps\n”
145 “\t5\t1080I @ 30 fps [Not supported for DM365]\n”
146 “\t6\t1080I @ 25 fps [Not supported for DM365]\n”
147 “You must supply at least a video or a speech file or both\n”
148 “with appropriate extensions for the file formats.\n\n”);
149 }
150
核心部分：参数解析的时候分短选项和长选项，那么shortOptions与longOptions就对应与两者，
其中shortOptions选项中如果加了“：”冒号，那么就需要带参数，而longOptions中通过“ required_argument”
与“ no_argument“来进行区分，最后把这两个参数传递给getopt_long函数就能逐一返回一个个选项，再根据选项
得到对应的参数，并将其存放在结构体中，整个过程就这样了；
151 /******************************************************************************
152 * parseArgs
153 ******************************************************************************/
154 static Void parseArgs(Int argc, Char *argv[], Args *argsp)
155 {
156 const Char shortOptions[] = “s:v:y:r:b:xlkt:oih”;
157 const struct option longOptions[] = {
158 {“speechfile”, required_argument, NULL, ‘s’},
159 {“videofile”, required_argument, NULL, ‘v’},
160 {“display_standard”, required_argument, NULL, ‘y’},
161 {“resolution”, required_argument, NULL, ‘r’},
162 {“videobitrate”, required_argument, NULL, ‘b’},
163 {“svideo”, no_argument, NULL, ‘x’},
164 {“linein”, no_argument, NULL, ‘l’},
165 {“keyboard”, no_argument, NULL, ‘k’},
166 {“time”, required_argument, NULL, ‘t’},
167 {“osd”, no_argument, NULL, ‘o’},
168 {“interface”, no_argument, NULL, ‘i’},
169 {“help”, no_argument, NULL, ‘h’},
170 {0, 0, 0, 0}
171 };
172
173 Int index;
174 Int c;
175 Char *extension;
176
177 for (;;) {
178 c = getopt_long(argc, argv, shortOptions, longOptions, &index);
179
180 if (c == -1) {
181 break;
182 }
183
184 switch (c) {
185 case 0:
186 break;
187
188 case ‘s’:
189 extension = rindex(optarg, ‘.’);
190 if (extension == NULL) {
191 fprintf(stderr, “Speech file without extension: %s\n”,
192 optarg);
193 exit(EXIT_FAILURE);
194 }
195
196 argsp->speechEncoder =
197 getCodec(extension, engine->speechEncoders);
198
199 if (!argsp->speechEncoder) {
200 fprintf(stderr, “Unknown speech file extension: %s\n”,
201 extension);
202 exit(EXIT_FAILURE);
203 }
204 argsp->speechFile = optarg;
205
206 break;
….
305 case ‘t’:
306 argsp->time = atoi(optarg);
307 break;
308
309 case ‘o’:
310 argsp->osd = TRUE;
311 break;
312
313 case ‘i’:
314 argsp->interface = TRUE;
315 break;
316
317 case ‘h’:
318 usage();
319 exit(EXIT_SUCCESS);
320
321 default:
322 usage();
323 exit(EXIT_FAILURE);
324 }
325 }
326
327 if (argsp->videoInput != Capture_Input_SVIDEO) {
328 if (argsp->videoStd == VideoStd_D1_NTSC || argsp->videoStd == VideoStd_D1_PAL ) {
329 argsp->videoInput = Capture_Input_COMPOSITE;
330 } else {
331 argsp->videoInput = Capture_Input_COMPONENT;
332 }
333 }
334
335 /* Need at least one file to decode and only one sound file */
336 if (!argsp->videoFile && !argsp->speechFile) {
337 usage();
338 exit(EXIT_FAILURE);
339 }
340 }
第三部分：主函数调用部分
388 /******************************************************************************
389 * main
390 ******************************************************************************/
391 Int main(Int argc, Char *argv[])
392 {
393 Args args = DEFAULT_ARGS;
426 /* Parse the arguments given to the app and set the app environment */
427 parseArgs(argc, argv, &args);
428 }
注意：头文件为 #include <getopt.h>，man 到的信息如下：
www.linuxidc.com@www.linuxidc.com:~/abs_guide/chapter3$ man -k getopt_long
getopt_long (3) – Parse command-line options
getopt_long_only (3) – Parse command-line options
