把C程序编译链接后,用exec()或是system()来调用它.以下是两者的说明:system (PHP 3, PHP 4 >= 4.0.0)system -- Execute an external program and display output Descriptionstring system (string command [, int return_var]) system() is just like the C version of the function in that it executes the given command and outputs the result. If a variable is provided as the second argument, then the return status code of the executed command will be written to this variable. Note, that if you are going to allow data coming from user input to be passed to this function, then you should be using the escapeshellcmd() function to make sure that users cannot trick the system into executing arbitrary commands. Note also that if you start a program using this function and want to leave it running in the background, you have to make sure that the output of that program is redirected to a file or some other output stream or else PHP will hang until the execution of the program ends. The system() call also tries to automatically flush the web server's output buffer after each line of output if PHP is running as a server module. Returns the last line of the command output on success, and FALSE on failure. If you need to execute a command and have all the data from the command passed directly back without any interference, use the passthru() function. exec (PHP 3, PHP 4 >= 4.0.0)exec -- Execute an external program Descriptionstring exec (string command [, string array [, int return_var]]) exec() executes the given command, however it does not output anything. It simply returns the last line from the result of the command. If you need to execute a command and have all the data from the command passed directly back without any interference, use the passthru() function. If the array argument is present, then the specified array will be filled with every line of output from the command. Note that if the array already contains some elements, exec() will append to the end of the array. If you do not want the function to append elements, call unset() on the array before passing it to exec(). If the return_var argument is present along with the array argument, then the return status of the executed command will be written to this variable. Note that if you are going to allow data coming from user input to be passed to this function, then you should be using escapeshellcmd() to make sure that users cannot trick the system into executing arbitrary commands. Note also that if you start a program using this function and want to leave it running in the background, you have to make sure that the output of that program is redirected to a file or some other output stream or else PHP will hang until the execution of the program ends.
(PHP 3, PHP 4 >= 4.0.0)system -- Execute an external program and display output
Descriptionstring system (string command [, int return_var])
system() is just like the C version of the function in that it executes the given command and outputs the result. If a variable is provided as the second argument, then the return status code of the executed command will be written to this variable. Note, that if you are going to allow data coming from user input to be passed to this function, then you should be using the escapeshellcmd() function to make sure that users cannot trick the system into executing arbitrary commands. Note also that if you start a program using this function and want to leave it running in the background, you have to make sure that the output of that program is redirected to a file or some other output stream or else PHP will hang until the execution of the program ends. The system() call also tries to automatically flush the web server's output buffer after each line of output if PHP is running as a server module. Returns the last line of the command output on success, and FALSE on failure. If you need to execute a command and have all the data from the command passed directly back without any interference, use the passthru() function. exec
(PHP 3, PHP 4 >= 4.0.0)exec -- Execute an external program
Descriptionstring exec (string command [, string array [, int return_var]])
exec() executes the given command, however it does not output anything. It simply returns the last line from the result of the command. If you need to execute a command and have all the data from the command passed directly back without any interference, use the passthru() function. If the array argument is present, then the specified array will be filled with every line of output from the command. Note that if the array already contains some elements, exec() will append to the end of the array. If you do not want the function to append elements, call unset() on the array before passing it to exec(). If the return_var argument is present along with the array argument, then the return status of the executed command will be written to this variable. Note that if you are going to allow data coming from user input to be passed to this function, then you should be using escapeshellcmd() to make sure that users cannot trick the system into executing arbitrary commands. Note also that if you start a program using this function and want to leave it running in the background, you have to make sure that the output of that program is redirected to a file or some other output stream or else PHP will hang until the execution of the program ends.