1、头文件
#include <fcgi_stdio.h>
2、while(FCGI_Accept()>=0)//这里进入循环，前台每请求一次fcgi服务，就循环一次
循环内处理：
char *query_string=getenv("QUERY_STRING");
3、从获得的query_string解析查询字段，进行后续操作。
4、用printf返回处理结果给web服务器，再由web服务器将结果返回给客户端。
（这里的printf函数是在fcgi_stdio.h中重新定义了的）
附：fcgi_stdio.h
/*
* fcgi_stdio.h -- * * FastCGI-stdio compatibility package * * * Copyright (c) 1996 Open Market, Inc. * * See the file "LICENSE.TERMS" for information on usage and redistribution * of this file, and for a DISCLAIMER OF ALL WARRANTIES. * * $Id: fcgi_stdio.h,v 1.5 2001/06/22 13:21:15 robs Exp $ */#ifndef _FCGI_STDIO
#define _FCGI_STDIO 1#include <stdio.h>
#include <sys/types.h>#include "fcgiapp.h"#if defined (c_plusplus) || defined (__cplusplus)
extern "C" { #endif#ifndef DLLAPI
#ifdef _WIN32#define DLLAPI __declspec(dllimport)#else#define DLLAPI#endif#endif/*
* Wrapper type for FILE */typedef struct {
FILE *stdio_stream; FCGX_Stream *fcgx_stream;} FCGI_FILE;/*
* The four new functions and two new macros */DLLAPI int FCGI_Accept(void);
DLLAPI void FCGI_Finish(void);DLLAPI int FCGI_StartFilterData(void);DLLAPI void FCGI_SetExitStatus(int status);#define FCGI_ToFILE(fcgi_file) (fcgi_file->stdio_stream)
#define FCGI_ToFcgiStream(fcgi_file) (fcgi_file->fcgx_stream)/*
* Wrapper stdin, stdout, and stderr variables, set up by FCGI_Accept() */DLLAPI extern FCGI_FILE _fcgi_sF[];
#define FCGI_stdin (&_fcgi_sF[0])#define FCGI_stdout (&_fcgi_sF[1])#define FCGI_stderr (&_fcgi_sF[2])/*
* Wrapper function prototypes, grouped according to sections * of Harbison & Steele, "C: A Reference Manual," fourth edition, * Prentice-Hall, 1995. */DLLAPI void FCGI_perror(const char *str);
DLLAPI FCGI_FILE *FCGI_fopen(const char *path, const char *mode);
DLLAPI int FCGI_fclose(FCGI_FILE *fp);DLLAPI int FCGI_fflush(FCGI_FILE *fp);DLLAPI FCGI_FILE *FCGI_freopen(const char *path, const char *mode, FCGI_FILE *fp);DLLAPI int FCGI_setvbuf(FCGI_FILE *fp, char *buf, int bufmode, size_t size);
DLLAPI void FCGI_setbuf(FCGI_FILE *fp, char *buf);DLLAPI int FCGI_fseek(FCGI_FILE *fp, long offset, int whence);
DLLAPI int FCGI_ftell(FCGI_FILE *fp);DLLAPI void FCGI_rewind(FCGI_FILE *fp);#ifdef HAVE_FPOSDLLAPI int FCGI_fgetpos(FCGI_FILE *fp, fpos_t *pos);DLLAPI int FCGI_fsetpos(FCGI_FILE *fp, const fpos_t *pos);#endifDLLAPI int FCGI_fgetc(FCGI_FILE *fp);DLLAPI int FCGI_getchar(void);DLLAPI int FCGI_ungetc(int c, FCGI_FILE *fp);DLLAPI char *FCGI_fgets(char *str, int size, FCGI_FILE *fp);
DLLAPI char *FCGI_gets(char *str);/*
* Not yet implemented * * int FCGI_fscanf(FCGI_FILE *fp, const char *format, ...); * int FCGI_scanf(const char *format, ...); * */DLLAPI int FCGI_fputc(int c, FCGI_FILE *fp);
DLLAPI int FCGI_putchar(int c);DLLAPI int FCGI_fputs(const char *str, FCGI_FILE *fp);
DLLAPI int FCGI_puts(const char *str);DLLAPI int FCGI_fprintf(FCGI_FILE *fp, const char *format, ...);
DLLAPI int FCGI_printf(const char *format, ...);DLLAPI int FCGI_vfprintf(FCGI_FILE *fp, const char *format, va_list ap);
DLLAPI int FCGI_vprintf(const char *format, va_list ap);DLLAPI size_t FCGI_fread(void *ptr, size_t size, size_t nmemb, FCGI_FILE *fp);
DLLAPI size_t FCGI_fwrite(void *ptr, size_t size, size_t nmemb, FCGI_FILE *fp);DLLAPI int FCGI_feof(FCGI_FILE *fp);
DLLAPI int FCGI_ferror(FCGI_FILE *fp);DLLAPI void FCGI_clearerr(FCGI_FILE *fp);DLLAPI FCGI_FILE *FCGI_tmpfile(void);
DLLAPI int FCGI_fileno(FCGI_FILE *fp);
DLLAPI FCGI_FILE *FCGI_fdopen(int fd, const char *mode);DLLAPI FCGI_FILE *FCGI_popen(const char *cmd, const char *type);DLLAPI int FCGI_pclose(FCGI_FILE *);/*
* The remaining definitions are for application programs, * not for fcgi_stdio.c */#ifndef NO_FCGI_DEFINES
/*
* Replace standard types, variables, and functions with FastCGI wrappers. * Use undef in case a macro is already defined. */#undef FILE
#define FILE FCGI_FILE#undef stdin
#define stdin FCGI_stdin#undef stdout#define stdout FCGI_stdout#undef stderr#define stderr FCGI_stderr#undef perror
#define perror FCGI_perror#undef fopen
#define fopen FCGI_fopen#undef fclose#define fclose FCGI_fclose#undef fflush#define fflush FCGI_fflush#undef freopen#define freopen FCGI_freopen#undef setvbuf
#define setvbuf FCGI_setvbuf#undef setbuf#define setbuf FCGI_setbuf#undef fseek
#define fseek FCGI_fseek#undef ftell#define ftell FCGI_ftell#undef rewind#define rewind FCGI_rewind#undef fgetpos#define fgetpos FCGI_fgetpos#undef fsetpos#define fsetpos FCGI_fsetpos#undef fgetc
#define fgetc FCGI_fgetc#undef getc#define getc FCGI_fgetc#undef getchar#define getchar FCGI_getchar#undef ungetc#define ungetc FCGI_ungetc#undef fgets
#define fgets FCGI_fgets#undef gets#define gets FCGI_gets#undef fputc
#define fputc FCGI_fputc#undef putc#define putc FCGI_fputc#undef putchar#define putchar FCGI_putchar#undef fputs
#define fputs FCGI_fputs#undef puts#define puts FCGI_puts#undef fprintf
#define fprintf FCGI_fprintf#undef printf#define printf FCGI_printf#undef vfprintf
#define vfprintf FCGI_vfprintf#undef vprintf#define vprintf FCGI_vprintf#undef fread
#define fread FCGI_fread#undef fwrite#define fwrite FCGI_fwrite#undef feof
#define feof FCGI_feof#undef ferror#define ferror FCGI_ferror#undef clearerr#define clearerr FCGI_clearerr#undef tmpfile
#define tmpfile FCGI_tmpfile#undef fileno
#define fileno FCGI_fileno#undef fdopen#define fdopen FCGI_fdopen#undef popen#define popen FCGI_popen#undef pclose#define pclose FCGI_pclose#endif /* NO_FCGI_DEFINES */
#if defined (__cplusplus) || defined (c_plusplus)
} /* terminate extern "C" { */#endif#endif /* _FCGI_STDIO */