The LC_COLLATE locale setting is then considered: only if LC_COLLATE=C or LC_ALL=C does strcmp() compare strings by character code. When both character entities have the same collation order (such as 'ss' and '?' in German), they are compared relative to their code by strcmp(), or considered equal by strcasecmp(). In summary, strcmp() does not necessarily use the ASCII code order of each character like in the 'C' locale, but instead parse each string to match language-specific character entities (such as 'ch' in Spanish, or 'dz' in Czech), whose collation order is then compared. Just the numerical values of the first letters are compared Produces the length of the NON-empty string. Then the remaining "fox" is compared to the remaing empty string in the other argument. (a,afox) = -3 // The identical BEGINNING part ("a") is trunkated from both strings. (,a) = -1 //comparing with an empty string produces the length of the NON-empty string In Apache/2.4.37 (Win32) OpenSSL/1.1.1 PHP/7.2.12 produces the following results: The result is +1 or -1 no matter how big is the difference between the numerical values.įor( $i = 0 $i ('. Str_split(trim(sz)) = Array ( => / => v => a => r => / => w => w => w )ġ) If the two strings have identical BEGINNING parts, they are trunkated from both strings.Ģ) The resulting strings are compared with two possible outcomes:Ī) if one of the resulting strings is an empty string, then the length of the non-empty string is returned (the sign depending on the order in which you pass the arguments to the function)ī) in any other case just the numerical values of the FIRST characters are compared. Str_split(ps) = Array ( => / => v => a => r => / => w => w => w )Ĭomparison with trim()'d zero-terminated string: strcmp ( $sz, $ps ) Įcho "Comparison with trim()'d zero-terminated string:" Įcho "str_split(trim(sz)) = " print_r ( str_split ( trim ( $sz ))) echo "" Įcho "trim(sz) = ps = ". "str_split(ps) = " print_r ( str_split ( $ps )) Įcho "sz = ps = ". "str_split(sz) = " print_r ( str_split ( $sz )) Įcho "Pascal-style string:ps = ". On Debian Lenny (and RHEL 5, with minor differences), I get this: This is likely to be an issue with other functions that invoke shells I haven't bothered to check. The workaround is to surround every `` pair or shell_exec() function with the trim() function. One big caveat - strings retrieved from the backtick operation may be zero terminated (C-style), and therefore will not be equal to the non-zero terminated strings (roughly Pascal-style) normal in PHP. Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Classes and Objects Namespaces Enumerations Errors Exceptions Fibers Generators Attributes References Explained Predefined Variables Predefined Exceptions Predefined Interfaces and Classes Predefined Attributes Context options and parameters Supported Protocols and Wrappers Security Introduction General considerations Installed as CGI binary Installed as an Apache module Session Security Filesystem Security Database Security Error Reporting User Submitted Data Hiding PHP Keeping Current Features HTTP authentication with PHP Cookies Sessions Dealing with XForms Handling file uploads Using remote files Connection handling Persistent Database Connections Command line usage Garbage Collection DTrace Dynamic Tracing Function Reference Affecting PHP's Behaviour Audio Formats Manipulation Authentication Services Command Line Specific Extensions Compression and Archive Extensions Cryptography Extensions Database Extensions Date and Time Related Extensions File System Related Extensions Human Language and Character Encoding Support Image Processing and Generation Mail Related Extensions Mathematical Extensions Non-Text MIME Output Process Control Extensions Other Basic Extensions Other Services Search Engine Extensions Server Specific Extensions Session Extensions Text Processing Variable and Type Related Extensions Web Services Windows Only Extensions XML Manipulation GUI Extensions Keyboard Shortcuts ? This help j Next menu item k Previous menu item g p Previous man page g n Next man page G Scroll to bottom g g Scroll to top g h Goto homepage g s Goto search
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