PHP exec () function no return value troubleshooting method

Source: Internet
Author: User

Exec is required for security imagemagic. Many servers fail to be installed.
Exec () failed to execute the external command, but there was no error message.

Exec executes a command in the command line, but an error occurs in PHP. This issue is 99.99% related to permissions, but the Command executed by exec will not return an error. One trick is to use the pipeline command. Assume that your exec call is as follows:

  1. Exec ('convert a.jpg B .jpg ', $ output, $ return_val );

Copy code

You can change it as follows:

  1. Exec ('convert a.jpg B .jpg 2> & 1', $ output, $ return_val );
  2. Print_r ($ output );

Copy code

With 2> & 1, the command will output the $ output variable error during shell execution, and output the variable for analysis.

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.