我已经在 Slackware 下安装了 Apache、mysqld。Apache 可以运行。但是脚本：
$dblocation="127.0.0.1";
$dbuser="root";
$dbpasswd="unfriendly_possum";
$dbcnx=mysql_connect($dblocation, $dbuser, $dbpasswd);
if(!$dbcnx)
{
echo("Error");
exit();
}
$dbq=mysql_query("select version();");
echo(mysql_result($dbq,0));
返回错误
Warning: mysql_connect() [function.mysql-connect]: Lost connection to MySQL server at 'reading initial communication packet', system error: 111 in /usr/local/httpd/htdocs/mysql.php on line 8
Error
救命啊（我哭了）
UPD 我已将 $dblocation="127.0.0.1" 更正为 "localhost"，但发生了另一个错误：
Warning: mysql_connect() [function.mysql-connect]: Can't connect to local MySQL server through socket '/var/run/mysql/mysql.sock' (2) in /usr/local/httpd/htdocs/mysql.php on line 8
Error
php 配置片段
[SQL]
sql.safe_mode = Off
[ODBC]
;odbc.default_db = Not yet implemented
;odbc.default_user = Not yet implemented
;odbc.default_pw = Not yet implemented
; Allow or prevent persistent links.
odbc.allow_persistent = On
; Check that a connection is still valid before reuse.
odbc.check_persistent = On
; Maximum number of persistent links. -1 means no limit.
odbc.max_persistent = -1
; Maximum number of links (persistent + non-persistent). -1 means no limit.
odbc.max_links = -1
; Handling of LONG fields. Returns number of bytes to variables. 0 means
; passthru.
odbc.defaultlrl = 4096
; Handling of binary data. 0 means passthru, 1 return as is, 2 convert to char.
; See the documentation on odbc_binmode and odbc_longreadlen for an explanation
; of uodbc.defaultlrl and uodbc.defaultbinmode
odbc.defaultbinmode = 1
[MySQL]
; Allow or prevent persistent links.
mysql.allow_persistent = On
; Maximum number of persistent links. -1 means no limit.
mysql.max_persistent = -1
; Maximum number of links (persistent + non-persistent). -1 means no limit.
mysql.max_links = -1
; Default port number for mysql_connect(). If unset, mysql_connect() will use
; the $MYSQL_TCP_PORT or the mysql-tcp entry in /etc/services or the
; compile-time value defined MYSQL_PORT (in that order). Win32 will only look
; at MYSQL_PORT.
mysql.default_port =
; Default socket name for local MySQL connects. If empty, uses the built-in
; MySQL defaults.
mysql.default_socket =
; Default host for mysql_connect() (doesn't apply in safe mode).
mysql.default_host =
; Default user for mysql_connect() (doesn't apply in safe mode).
mysql.default_user =
; Default password for mysql_connect() (doesn't apply in safe mode).
; Note that this is generally a *bad* idea to store passwords in this file.
; *Any* user with PHP access can run 'echo get_cfg_var("mysql.default_password")
; and reveal this password! And of course, any users with read access to this
; file will be able to reveal the password as well.
mysql.default_password =
; Maximum time (in seconds) for connect timeout. -1 means no limit
mysql.connect_timeout = 60
; Trace mode. When trace_mode is active (=On), warnings for table/index scans and
; SQL-Errors will be displayed.
mysql.trace_mode = Off
[MySQLi]
; Maximum number of links. -1 means no limit.
mysqli.max_links = -1
; Default port number for mysqli_connect(). If unset, mysqli_connect() will use
; the $MYSQL_TCP_PORT or the mysql-tcp entry in /etc/services or the
; compile-time value defined MYSQL_PORT (in that order). Win32 will only look
; at MYSQL_PORT.
mysqli.default_port = 3306
; Default socket name for local MySQL connects. If empty, uses the built-in
; MySQL defaults.
mysqli.default_socket =
; Default host for mysql_connect() (doesn't apply in safe mode).
mysqli.default_host =
; Default user for mysql_connect() (doesn't apply in safe mode).
mysqli.default_user =
; Default password for mysqli_connect() (doesn't apply in safe mode).
; Note that this is generally a *bad* idea to store passwords in this file.
; *Any* user with PHP access can run 'echo get_cfg_var("mysqli.default_pw")
; and reveal this password! And of course, any users with read access to this
; file will be able to reveal the password as well.
mysqli.default_pw =
; Allow or prevent reconnect
mysqli.reconnect = Off
[mSQL]
; Allow or prevent persistent links.
msql.allow_persistent = On
; Maximum number of persistent links. -1 means no limit.
msql.max_persistent = -1
; Maximum number of links (persistent+non persistent). -1 means no limit.
msql.max_links = -1
my.cnf 部分：
[mysqld]
log =/var/log/mysqld/mysqld.log
port = 3306
socket = /tmp/mysql.sock
skip-locking
key_buffer = 16M
max_allowed_packet = 1M
table_cache = 64
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
# Don't listen on a TCP/IP port at all. This can be a security enhancement,
# if all processes that need to connect to mysqld run on the same host.
# All interaction with mysqld must be made via Unix sockets or named pipes.
# Note that using this option without enabling named pipes on Windows
# (via the "enable-named-pipe" option) will render mysqld useless!
#
#skip-networking
# Disable Federated by default
skip-federated
# Replication Master Server (default)
# binary logging is required for replication
log-bin=mysql-bin
# required unique id between 1 and 2^32 - 1
# defaults to 1 if master-host is not set
# but will not function as a master if omitted
server-id = 1
# Replication Slave (comment out master section to use this)
#
# To configure this host as a replication slave, you can choose between
# two methods :
#
# 1) Use the CHANGE MASTER TO command (fully described in our manual) -
# the syntax is:
#
# CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=<port>,
# MASTER_USER=<user>, MASTER_PASSWORD=<password> ;
#
# where you replace <host>, <user>, <password> by quoted strings and
# <port> by the master's port number (3306 by default).
#
# Example:
#
# CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,
# MASTER_USER='joe', MASTER_PASSWORD='secret';
#
# OR
#
# 2) Set the variables below. However, in case you choose this method, then
# start replication for the first time (even unsuccessfully, for example
# if you mistyped the password in master-password and the slave fails to
# connect), the slave will create a master.info file, and any later
# change in this file to the variables' values below will be ignored and
# overridden by the content of the master.info file, unless you shutdown
# the slave server, delete master.info and restart the slaver server.
# For that reason, you may want to leave the lines below untouched
# (commented) and instead use CHANGE MASTER TO (see above)
#
# required unique id between 2 and 2^32 - 1
# (and different from the master)
# defaults to 2 if master-host is set
# but will not function as a slave if omitted
#server-id = 2
#
# The replication master for this slave - required
#master-host = <hostname>
#
# The username the slave will use for authentication when connecting
# to the master - required
#master-user = <username>
#
# The password the slave will authenticate with when connecting to
# the master - required
#master-password = <password>
#
# The port the master is listening on.
# optional - defaults to 3306
#master-port = <port>
#
# binary logging - not required for slaves, but recommended
#log-bin=mysql-bin
# Point the following paths to different dedicated disks
#tmpdir = /tmp/
#log-update = /path-to-dedicated-directory/hostname
# Uncomment the following if you are using BDB tables
#bdb_cache_size = 4M
#bdb_max_lock = 10000
# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /usr/local/mysql/var/
#innodb_data_file_path = ibdata1:10M:autoextend
#innodb_log_group_home_dir = /usr/local/mysql/var/
#innodb_log_arch_dir = /usr/local/mysql/var/
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 16M
#innodb_additional_mem_pool_size = 2M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 5M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates
答案1
检查 MySQL 日志文件中是否有关于此错误的信息。如果要使用 MySQL Unix 套接字进行连接，请更改此行：
socket = /tmp/mysql.sock
到
socket = /var/run/mysql/mysql.sock
这应该可以解决这个问题。
答案2
尝试：
$dblocation="localhost";
答案3
MySql 正在运行吗？PHP 在其配置文件 (/etc/php.ini) 中是否正确设置为连接到它？
答案4
MySQL 已在 /tmp/mysqld.sock 中打开了一个套接字，但 PHP 正在寻找套接字 /var/run/mysql/mysql.sock。
您要么让 PHP 查看 /tmp/mysql.sock，要么让 MySQL 在 /var/run/mysql/mysql/sock 中创建套接字 - 就像 Kedare 建议的那样。
更改 PHP 造成的破坏较少。您的配置文件有两个条目：
mysql.default_socket =
将这两项都更改为（只有一项有效，但我不知道是哪一个）：
mysql.default_socket = /tmp/mysql.sock
MySQL 有点奇怪：对于 MySQL 客户端，“localhost”意味着使用 UNIX 域套接字连接到数据库。
我有一种感觉，修复这个部分只会让你回到原来的问题：
Lost connection to MySQL server at 'reading initial communication packet', system error: 111
这听起来像是客户端和服务器版本不兼容。您是否使用 3.23 库与 5.1 服务器通信？