What are these errors?

[landyvlad]

I've been getting a LOT of errors of a specific type recently and have no idea what they are or of course how to resolve them.

Does anyone have any ideas about these? 

ERROR 1

Guest
 85.208.96.207
 b5127c0abd624ecc26773f6b20fdd4c4
 https://gsx1400owners.org/forum/index.php?topic=4041.0%3Bprev_next%3Dprev
 /home2/gsxowner/public_html/forum/Sources/Subs.php (Line 4529)  Backtrace information

Type of error: General
Error messageSelect
2: Cannot modify header information - headers already sent by (output started at __mnx_runtime:1)

Backtrace info is:

Error
Type of error
General
Error message
2: Cannot modify header information - headers already sent by (output started at __mnx_runtime:1)
File
/home2/gsxowner/public_html/forum/Sources/Subs.php
Line
4529
URL of page causing the error
https://gsx1400owners.org/forum/index.php?topic=4041.0%3Bprev_next%3Dprev
Backtrace information
#0: smf_error_handler()
Called from unknown on line -1
#1: header()
Called from /home2/gsxowner/public_html/forum/Sources/Subs.php on line 4529
#2: template_header()
Called from /home2/gsxowner/public_html/forum/Sources/Subs.php on line 4157
#3: obExit()
Called from /home2/gsxowner/public_html/forum/index.php on line 187

ERROR 2

Guest
 https://gsx1400owners.org/forum/index.php?topic=290.0
 /home2/gsxowner/public_html/forum/Sources/Session.php (Line 81)  Backtrace information

Type of error: General
Error messageSelect
2: session_start(): Session cannot be started after headers have already been sent

backtrace info:

Type of error
General
Error message
2: session_start(): Session cannot be started after headers have already been sent
File
/home2/gsxowner/public_html/forum/Sources/Session.php
Line
81
URL of page causing the error
https://gsx1400owners.org/forum/index.php?topic=290.0
Backtrace information
#0: smf_error_handler()
Called from unknown on line -1
#1: session_start()
Called from /home2/gsxowner/public_html/forum/Sources/Session.php on line 81
#2: loadSession()
Called from /home2/gsxowner/public_html/forum/index.php on line 181

ERROR 3

Guest
 https://gsx1400owners.org/forum/index.php?topic=7374.0
 /home2/gsxowner/public_html/forum/Sources/Session.php (Line 71)  Backtrace information

Type of error: General
Error messageSelect
2: session_set_save_handler(): Session save handler cannot be changed after headers have already been sent

Backtrace info:

Type of error
General
Error message
2: session_set_save_handler(): Session save handler cannot be changed after headers have already been sent
File
/home2/gsxowner/public_html/forum/Sources/Session.php
Line
71
URL of page causing the error
https://gsx1400owners.org/forum/index.php?topic=7374.0
Backtrace information
#0: smf_error_handler()
Called from unknown on line -1
#1: session_set_save_handler()
Called from /home2/gsxowner/public_html/forum/Sources/Session.php on line 71
#2: loadSession()
Called from /home2/gsxowner/public_html/forum/index.php on line 181

Any assistance as to what causes this and how to fix it is most welcome.

[Doug Heffernan]

They seem to be generated by space at the start of php file(s),  before the php tag. What was the latest change done to the forum prior to those errors happening?

[landyvlad]

I have no idea. No changes for a while but also I only just saw these errors but they have been happening a while.

Are there any easy first steps to try to at least rule things out? I.e. repair settings?

[GL700Wing]

I have no idea. No changes for a while but also I only just saw these errors but they have been happening a while.

Are there any easy first steps to try to at least rule things out? I.e. repair settings?

@landyvlad Start by listing all the PHP files across your whole forum in reverse order by date modified and then check each one individually to make sure that the first line only contains the following characters with no leading whitespace (eg, spaces, tabs, etc):

Code Select Expand

<?php

[Sesquipedalian]

It's also possible that you have trailing whitespace at the end of one of your PHP files. In all versions prior to 3.0, SMF used closing PHP tags in all of its PHP files. If you manually edited one of those files, you might have accidentally added some whitespace after its closing PHP tag. If so, that would also cause the issue you are experiencing.