I am using php4 RC1 to parse a file that is uploaded from a user.

file opens correctly, and all other characters are taken out when I use either ereg_replace or eregi_replace. However, 

trim($str)  
ltrim($str)
fail to remove the beginning and trailing whitespaces.

eregi_replace(" ", "", $str)
ereg_replace(" ", "", $str)
eregi_replace("[[:space:]]", "", $str)
ereg_replace("[[:space:]]", "", $str)
these also fail to remove a space at the beginning of a string that I'm reading from an uploaded text file.

I'm running:
System: SunOS jasonwolfe.com 5.7 Generic_106541-10 sun4c sparc SUNW,Sun_4_75
Apache 1.3.12
MySQL 3.22.32