What should I do if php exec cannot get the value?

Solution to the problem that php exec cannot obtain the value: 1. Open the corresponding PHP code file; 2. Modify the code to "exec('convert a.jpg b.jpg 2>&1', $output, $ return_val);" That's it.

#The operating environment of this article: Windows 7 system, PHP version 7.4, Dell G3 computer.

What should I do if php exec cannot get the value?

PHP's exec() function has no return value Troubleshooting method:

Exec is needed to secure imagemagic and the installation fails on many servers

exec() execution The external command fails without any error message.

There is no problem when exec executes a certain command on the command line, but an error occurs in PHP. This problem is 99.99% related to permissions, but the command executed by exec will not return an error. One trick is to use a pipeline command. Suppose your exec call is as follows:

exec('convert a.jpg b.jpg', $output, $return_val);

can be changed as follows:

exec('convert a.jpg b.jpg 2>&1', $output, $return_val);    
print_r($output);

Use 2>&1, the command will output the error during shell execution to the $output variable , output this variable to analyze.

Note: exec has 3 parameters. The first is the command to be executed. The second parameter is an array. The value of the array is generated after the first command is executed. , the execution status of the third parameter, 0 indicates success, others indicate failure.

There are three functions in php that can be used to execute external commands system, exec, and passthru.

Recommended learning: "PHP Video Tutorial"

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