file_put_contents() saves the image and returns the value after the function succeeds

When I saved the image today, I used file_put_contents() to save the image. I ran it several times, but no data came out. I thought this function failed to operate

So I checked the usage and return value of this function and found that the returns I output were all correct. Later I found out that it was caused by other reasons

Now share the usage of this function:

The file_put_contents() function is the most suitable choice for writing strings or appending string contents to a file at once.

The file_put_contents() function is used to write a string to a file. It returns the number of bytes of data written to the file successfully, and returns FALSE if it fails.

Grammar:

int file_put_contents ( string filename, string data [, int flags [, resource context]] )
Parameter Description: Parameter Description
filename The name of the file to write data to
data The data to be written. The type can be string, array (but not multi-dimensional array), or stream resource
flags are optional and specify how to open/write the file. Possible values:
FILE_USE_INCLUDE_PATH: Check the built-in path for a copy of filename
FILE_APPEND: Write data by appending to the end of the file
LOCK_EX: Lock the file

context is optional. Context is a set of options through which text attributes can be modified

Example:

echo file_put_contents("test.txt", "This is something.");
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Running this example, the browser output:

18
The content of the test.txt file (in the same directory as the program) is: This is something..