Seamer Michael Hogan claimed his 100th wicket of the season as Glamorgan restricted Gloucestershire on the opening day of their LV= County Championship match at Cardiff.
Chris Dent hit 84 as Gloucestershire reached 228-8 in their first innings from 82.1 overs before bad light ended play at 5.30pm.
It was Glamorgan's first game since they went down to Nottinghamshire in last Saturday's Yorkshire Bank 40 final at Lord's.
The Welsh county made three changes to their side which drew last week with Essex at Chelmsford with Jim Allenby, Graham Wagg and David Lloyd replacing Will Bragg, Andrew Salter and John Glover.
The hosts won the toss and put Gloucestershire in to bat in helpful bowling conditions and Hogan struck at the start of the seventh over to reach the landmark by bowling opener Gareth Roderick.
But from 12-1, Gloucestershire recovered either side of lunch with Dent reaching his half-century from 77 balls shortly before the interval.
By lunch the visitors looked quite well set but in the afternoon they struggled going from 90-1 to 176-6.
With the total on 90 Allenby bowled Alex Gidman and Dent, who had looked well set for a century, edged slow left armer Dean Cosker into the Australian's hands at slip to make it 132-3.
Cosker struck again next ball to have Iain Cockbain also caught at slip by Allenby from a turning delivery.
With the total on 156 Gloucestershire lost Hamish Marshall, who is 10 short of reaching 1,000 runs for the season, as he edged Wagg behind.
In the penultimate over before tea Cameron Herring was trapped lbw by Hogan.
Ruaidhri Smith struck twice bowling Benny Howell and then had Gidman caught behind.
Glamorgan took the second new ball, but with the cloud cover having increased, the light deteriorated and forced the players off with 13.5 overs left of the day.